Abstract
SummaryOne of the major challenges for plant scientists is increasing wheat (Triticum aestivum) yield potential (YP). A significant bottleneck for increasing YP is achieving increased biomass through optimization of radiation use efficiency (RUE) along the crop cycle. Exotic material such as landraces and synthetic wheat has been incorporated into breeding programmes in an attempt to alleviate this; however, their contribution to YP is still unclear. To understand the genetic basis of biomass accumulation and RUE, we applied genome‐wide association study (GWAS) to a panel of 150 elite spring wheat genotypes including many landrace and synthetically derived lines. The panel was evaluated for 31 traits over 2 years under optimal growing conditions and genotyped using the 35K wheat breeders array. Marker‐trait association identified 94 SNPs significantly associated with yield, agronomic and phenology‐related traits along with RUE and final biomass (BM_PM) at various growth stages that explained 7%–17% of phenotypic variation. Common SNP markers were identified for grain yield, BM_PM and RUE on chromosomes 5A and 7A. Additionally, landrace and synthetic derivative lines showed higher thousand grain weight (TGW), BM_PM and RUE but lower grain number (GM2) and harvest index (HI). Our work demonstrates the use of exotic material as a valuable resource to increase YP. It also provides markers for use in marker‐assisted breeding to systematically increase BM_PM, RUE and TGW and avoid the TGW/GM2 and BM_PM/HI trade‐off. Thus, achieving greater genetic gains in elite germplasm while also highlighting genomic regions and candidate genes for further study.
Highlights
Landrace and synthetic material have been identified with superior biomass in comparison with elite lines under drought and heat conditions (Cossani and Reynolds, 2015; Lopes and Reynolds, 2011) and elite lines that include landrace or synthetic material in their background have been developed in recent years for heat and yield potential conditions (Reynolds et al, 2017)
Yield traits along with biomass and radiation use efficiency (RUE) were measured at key growth stages to establish the phenotypic variation present in a panel formed after screening a range of elite International Maize and Wheat Improvement Center (CIMMYT) spring wheat germplasm
The 150 elite lines were evaluated during two consecutive years under similar and optimal growth conditions with a shorter cycle during Y17 probably associated with higher temperatures registered (Table S1)
Summary
Landrace and synthetic material have been identified with superior biomass in comparison with elite lines under drought and heat conditions (Cossani and Reynolds, 2015; Lopes and Reynolds, 2011) and elite lines that include landrace or synthetic material in their background have been developed in recent years for heat and yield potential conditions (Reynolds et al, 2017). These new elite landrace and synthetic lines are derived from parents selected for expressing higher biomass and/or RUE (Reynolds et al, 2017).
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